Cam and ice machine combination

ABSTRACT

This specification discloses a machine for making ice cubes in an inverted tray having a closure platen and having an improved cam for forcing the platen open at the beginning of the harvest cycle. In its preferred form a double eccentric cam is used. Generally there is clearance or slack that must be taken up at the beginning of cam rotation before maximum force is required. The cam is so oriented relative to the follower that maximum force is developed by the cam at a point of rotation after the slack has been taken up between the parts and also at a time when the platen is to be broken loose from the ice. The force is applied to the platen continuously through the entire time the platen is being broken away from the ice.

Unite States Patent Kuebler [151 3,654,771 [451 Apr. 11, 1972 C AND ICEMAHINE COMBINATION [72] Inventor: Thomas L. Kuebler, 225 IllinoisAvenue,

Erie, Pa. 16505 [22] Filed: Jan. 19, 1970 [21] Appl. No.: 3,620

Primary Examiner-William E. Wayner Attorney-Charles L. Lovercheck [57]ABSTRACT This specification discloses a machine for making ice cubes inan inverted tray having a closure platen and having an improved cam forforcing the platen open at the beginning of the harvest cycle. In itspreferred form a double eccentric cam is used. Generally there isclearance or slack that must be taken up at the beginning of camrotation before maximum force is required. The cam is so orientedrelative to the follower that maximum force is developed by the cam at apoint of rotation after the slack has been taken up between the partsand also at a time when the platen is to be broken loose from the ice.The force is applied to the platen continuously through the entire timethe platen is being broken away from the ice.

5 Claims, 7 Drawing Figures PATENTEDAPR 11 I972 33, 654. 771

sum 1 UF 3 2/ 21 IN VEN TOR THOMAS L. KUIBLER QM W PATENTEDAPRHIHIB3,654,771

' SHEET 3 BF 3 FIG. 6. F G? 3 THOMAS KUEBLEK CAM AND ICE MACHINECOMBINATION STATEMENT OF INVENTION This invention relates to ice cubemaking machines and, more particularly, to ice cube machines incombination with an improved cam wherein an inverted refrigerated icecube tray receives jets of water for forming cubes and a swinging platencloses the bottom of the tray to form square ended cubes.

REFERENCE TO PRIOR ART An ice cube machine of the type disclosed hereinis shown in Bayston-Kuebler US. Pat. No. 3,009,336.

OBJECTS OF THE INVENTION It is an object of the invention to provide animproved combination ice cube machine and cam for opening the platenduring the harvest cycle.

Another object is to provide an improved ice cube machine.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross sectionalview of an ice cube machine according to the invention.

FIG. 2 is a longitudinal cross sectional view of the machine taken atanother plane through the center of the tray.

FIG. 3 is a view of a double eccentric cam.

FIG. 4 is another view of the double eccentric cam.

FIG. 5 is another view of the double eccentric cam.

FIG. 6 is a front view of a double eccentric cam.

FIG. 7 is a side view of the cam shown in FIG. 6.

DETAILED DESCRIPTION OF THE DRAWINGS The machine disclosed may be madeup of sectional freezing units 11 which may be stacked on base section10. Each section 11 will be made up of an enclosed cabinet 22 which maybe suitably insulated to prevent the loss of heat in a manner well knownto those skilled in the art. The top of the machine will be providedwith a suitable access cover 12 through which access may be had to themechanism of the machine.

The base is the ice storage bin with bottom 15, back wall 7 14 and endwalls 13, and has a door 16 hinged at 17 at the bottom. Adjustable feet21 at the corners of the base permit leveling the machine.

Each of the freezing units 11 has a partition 26 which separates theevaporator housing 27 from the compression housing 28.

Located in compartment 28 is the refrigeration system comprising thecompressor 51, condensing coil 53, fan 54, heat exchanger 56,refrigerant tank 61, hot gas bypass valve 71, and pressure valve 79.

The freezing apparatus enclosed in cabinet 22 will be familiar to thoseskilled in the art and similar to that disclosed in US. Pat. No.3,009,336.

The freezing mechanism is characterized by a freezing evaporatorgenerally indicated at 31 consisting of metallic grid having marginalwalls 32 and shorter intersecting partition walls 33 all secured on theunderside of a top plate 34 to form a multiplicity of individually openbottomed freezing cells 35. The open bottoms of the individual freezingcells are arranged to be closed during the freezing cycle of the machineby flat water plate 36 mounted in a rectangular frame 37 which is inturn pivoted on the pins 38 by a hinge 39. The hinged arrangement issuch that the water plate may be raised into contact with the freezingcell grid in a position indicated at A, when the freezing cycle is inprocess.

Water for the cubes to be frozen is externally provided throughconnection 75 and controlled by solenoid valve 76. The water is passedthrough line 77 to top plate 34, through holes 78 into chambers 35,precooling and passing out through holes in water plate 36 to the tank92. A recirculating pump 96 passes the water from the tank 92 throughbaffle tube 97, filter 98, header 95, tubes 94 with perforations 93 tofreezing cells 35. Some of the water is frozen to the periphery of thecells 35 and some recirculates to the tank 92, until the cubes arecomplete in the cells 35. The water plate 36 may thereafter be loweredto position B to permit release and discharge of the ice cubes from thefreezing cells as will hereinafter be described.

The rocking movement of the freezer plate is accomplished by a motorconnected through appropriate reduction gearing to the operator shaft 42having paired arms 43, each con nected by a tension spring 44 to alateral stud 45 projecting from the water plate 36. Thus, when the motoris rotated to swing the arms 43 upward to the position A, the tensionsprings 44 will be slightly extended to hold the water plate snugly butresiliently against the bottom edges of the freezing cell walls.

Downward swinging movement of the water plate 36 and its frame away fromthe freezing cells 35 is accomplished by energizing the motor to movethe shaft 42 approximately a half turn. This causes the parts to swingfrom position A to position B and allow the water plate 36 to assume anangle of about 30 degrees to the horizontal. It will be noted that thearms 43 are each provided with a cam surface 47 arranged to engage thetop edges of the water plate frame and urge the frame 37 downwardly withsufficient force to loosen it from the ice cube grid 31 after thefreezing operation has taken place.

Releasing the ice cubes formed in the cells 35 is accomplished byheating the cells 35 with hot gases introduced into the evaporator coil65 by valve 71 in the manner disclosed in US. Pat. No. 3,009,336. Thecubes fall from the cells 35 and are directed by the water plate 36 tothe chute 141 through which they fall into the bin 10.

A drainage system removes excess water from the bin 10 through tubes 132and 133 into trap 134 and out by connection 135. A tube 83 from thedrain pan 82 of the freezing section 11 collects the overflow water fromtank 92 and the freezing cells 35 and plate 36 which deflector platesI42 prevent from flowing into the ice chute 141.

The control system may be, for example, the same as shown in U.S. Pat.No. 3,009,336. The armature 46, the pilot water tank and water levelswitch 107, nozzle 118, switch 125, switch 131, actuator 139, activatorof the control are shown.

It is the cam 47 in combination with the machine that constitutes thesubject matter of the present invention.

The US. Pat. No. 3,009,336 discloses a simple cam. The machines withwhich applicant is familiar, which have been made according to thispatent, have used a circular cam on a shaft to force the water plateaway from the ice cubes formed in the ice cube tray shown in saidpatent. In the machine made according to the said patent, there isconsiderable slack between the parts of the machine and some strainmovement takes place between various parts before maximum force isrequired to break the plate loose from the ice tray. This totalpreliminary movement may be up to one-third of the total travel of thecam.

The rate of linear travel of a cam follower varies with the reciprocalof the moment arm. The moment arm is the perpendicular from the shaftcenter to the line through the eccentric center parallel to thedirection of travel.

For example, a cam that is vertically eccentric and a flat followertravelling vertically with 90 shaft turn delivering a travel of 1.5, themoment arm is zero at start and increases to 1.5 at finish. Rate oftravel is, therefore, zero at start and increases to maximum at finish.Deliverable force is theoretically infinite at start and decreases to0.667 (minimum) at finish. With the vertical cam, the force availablehas dropped from infinite to less than 1.0 in less than a third of thetravel of the follower and the force continues to drop during the nextpart of travel when needed most.

A better cam is a perfect spiral involute, which has a constant momentarm (the radius of the development circle), and

thus a constant force available through the whole travel. For a totaltravel in 90 of 1.5, the moment arm is 3/11, thus the force is 1r/3 or1.05. A perfect spiral involute is difficult to make and a 45 offseteccentric gives a fair approximation of it. For total travel of 1.5, theeccentricity begins at 0.75, increases to and decreases back to 0.75.The force available thus varies from 1.33 to 0.943 at mid point oftravel and back to 1.33 at end of travel. Compared to the verticaleccentric, the offset eccentric takes up the slack quicker and has aforce greater from about the one-fourth travel point on and a minimumforce 41 percent greater than the minimum force of the verticaleccentric.

Even though the offset eccentric is better than the vertical eccentric,it still produces more force during slack take up than it does when thegreatest force is needed at about the one-third travel point. Also itproduces more force at the end of the travel when the needed force isusually reduced during the overtravel period.

A much superior cam (even superior to a perfect spiral involute) is onewhose force peaks at the point of travel where the needed force isgreatest and whose force is less during slack take up and duringovertravel. The cam which produces this type of force curve is a doubleeccentric whose moment arm (instead of increasing during slack take up,or remaining constant per spiral) decreases during slack take up,reaches a minimum near the point of greatest needed force and thenincreases during overtravel. Instead of having a single radius, as dothe vertical and offset eccentric cams, the double eccentric cam hascurves with two different radii in the operational area, with thesmaller radius effective first then the large radius, with the junctureor tangent point in line with the line running through the radiiscenters. The smaller radius (Rs) may be any practical or convenientradius, the larger radius (RL) is the smaller radius plus the centerline distance.

When the cam is at rotation, (l if the center (Cs) of the smaller radiusis on the horizontal axis (X) and the center (CL) of the larger radiusis on the vertical axis (Y) with respect to the center of rotation ofthe cam, the center line distance (D) equals the total linear traveldelivered for 90 rotation; see FIG. 3; (2) If Cs is below X axis, D isincreased by Cs displacement from X axis; (3) If Cl is off the Y axisaway from Cs, D is increased by that displacement, (4) If Cs is abovethe X axis or Cl is off the Y axis toward Cs, D is reduced by the sum ofthese displacements. This (4) is not a preferred design as it reducesthe effectiveness of the double eccentric and carried to the ultimate(each displacement equal to half the total travel), the cam becomes asingle offset eccentric. The peak force occurs when the cam rotates thecenter line to the vertical as the moment arm is then smallest being theperpendicular from the shaft to the center line. This rotation is equalto the angle between the Y axis and the center line. The ratio of travelto this point compared to total travel is equal to the sine squared ofthis angle. The desired ratio is thus equated to the sine squared todetermine the correct angle. i.e. If peak force is desired at one-fourthtravel, then sine squared of the angle equals 0.25 and sine of the angleis 0.25 which equals 0.5 and the angle is 30. If peak force is desiredat one-half travel, the angle is 45, etc. In the example shown in FIGS.3, 4, 5, which is a preferred embodiment of the invention, the angle isthe small angle ofa 3, 4, 5, triangle, whose sine is 0.6, sine squaredis 0.36 so peak force occurs at 36 percent of total travel; Cs and CLare placed on X axis and Y axis, so that D is 1.5 to give total travelof 1.5.

FIG. 3 shows the cam at 0 rotation, the moment arm MA is 0.9, therelative force is l/O.9 1.1 l, the vertical travel is 0.

FIG. 4 shows the same cam at 3650 rotation counterclockwise, the momentarm MA is 0.72 at its minimum, the relative force is l/0.72 1,39 itsmaximum. The vertical travel is 0.54 36 ofthe 1.5 designed travel.

FIG. 5 shows the cam at 90 rotation counterclockwise to its designlimit, the moment arm MA is 1.2, the relative force is H1 .2 0.83, itsdesign minimum. The travel is 1.5 100 percent of the 1.5 designedtravel.

The foregoing specification sets forth the invention in its preferredpractical forms but the structure shown is capable of modificationwithin a range of equivalents without departing from the invention whichis to be understood is broadly novel as is commensurate with theappended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In a machine for manufacturing ice comprising an evaporator unitincluding a plurality of open bottom ice forming cells,

means for introducing a liquid to be frozen into said cells to besubjected to alternate freezing and defrosting cycles,

a platen movable to evaporator closing position during an ice freezingcycle and to an open ice discharge position during a defrosting cycle,wherein ice is formed in said cells and upon said platen during thefreezing cycle and freed from said cells during the defrosting cycle,

a cam shaft mounted on said machine above said platen,

a cam on said shaft engageable with said platen,

and power means operable following the said freezing cycle to actuatesaid cam shaft and cam to depress said platen for forced separation fromsaid evaporator and ice upon said cam being rotated to one position andpermit said platen to close said evaporator when said cam is moved toanother position,

said cam having a first part having a first center of curvature and asecond part having a second center of curvature,

said cam being mounted on said shaft at a position spaced from saidfirst center of curvature and from said second center of curvaturewhereby a double eccentric cam is formed,

said cam being adapted to move said platen first through a largeexcursion with a small force to take up slack in the platen, thenthrough a small excursion with a larger force to move said platen open.

2. In a machine for manufacturing ice comprising an evaporator unitincluding a plurality of open bottom ice forming cells,

means for introducing a liquid to be frozen into said cells ing cycle,wherein ice is formed in said cells and upon said platen during saidfreezing cycle and freed from said cells during said defrosting cycle,

a cam shaft mounted on said machine extending over said platen adjacentthe free end thereof,

a cam on said shaft engageable with the free end of said platen,

and power means operable to rotate said shaft and cam one revolutionfollowing the said freezing cycle for moving cam from a position topermit said platen to close said evaporator to a position to break itaway from the ice formed therein and permit free swinging thereof to itsopen ice discharging position,

said cam having a first part having a first center of curvature and asecond part having a second center of curvature,

said cam being mounted on said shaft disposed at a position spaced fromsaid first center of curvature and from said second center of curvature,and adapted to exert a force of small magnitude to take up slack, aforce of large magnitude to break said platen loose from said ice, thena force of small magnitude to force said platen open, during threesubstantially equal angular excursions of said cam respectively.

3. In a machine for manufacturing ice comprising an evaporator unitincluding a plurality of open bottom ice forming cells,

a platen movable into and away from sealing engagement with saidevaporator,

a liquid supply tank carried by said platen,

a liquid supply head in said platen having a spray nozzle directedupwardly and centrally of each cell and a waste drainage port leadingtherefrom to said supply tank,

and a pump carried by said platen adjacent said tank having its inletconnected with said tank and its discharge connected with said spraynozzles for circulating the liquid to be frozen through said cells andtank, the platen, supply tank, pump and liquid passage therebetweenbeing a rigid unitary structure and hinged at one end of the platen topermit said structure to swing downwardly and away from the under sideof said evaporator,

and power means operable between another edge of the platen andevaporator for forcibly breaking the ice seal,

a cam having a first part having a first center of curvature and asecond part having a second center of curvature,

said cam being mounted on a shaft disposed at a position spaced fromsaid first center of curvature and from said second center of curvature,

said cam adapted to exert a force of small magnitude to take up slack, aforce of large magnitude to break said platen loose from said ice, thena force of small magnitude to force said platen open, during threesubstantially equal angular excursions of said cam respectively.

4. In a machine for manufacturing ice comprising an evaporator unitincluding a plurality of open bottom ice forming cells,

a platen movable into and away from sealing engagement with saidevaporator,

a liquid supply head in said platen having a spray nozzle directedupwardly into each cell and a waste drainage port leading therefrom,

a liquid supply tank secured to and carried by said platen,

a pump mounted on said platen having its inlet connected with said tankand its discharge connected with said spray nozzles for circulating theliquid tobe frozen through said cells and tank,

a source of liquid connected with said tank having a control valve,

and a float in said tank operably connected with said valve for limitingthe liquid level therein,

said platen, liquid supply head, supply tank, pump and interconnectingpassages being assembled as a rigid unitary structure and relativelymovable as a unit with respect to said evaporator,

a cam having a first part having a first center of curvature and asecond part having a second center of curvature,

said cam being mounted on a shaft disposed at a position spaced fromsaid first center of curvature and from said second center of curvature,

said cam adapted to exert a force of small magnitude to take up slack, aforce of large magnitude to break said platen loose from said ice, thena force of small magnitude to force said platen open, during threesubstantially equal angular excursions of said cam respectively.

5. In a machine for manufacturing ice comprising an evaporator unitincluding a plurality of open bottom ice forming cells,

a platen,

said platen being hinged at one side to swing into and away from sealingengagement with said evaporator,

a liquid supply head in said platen having a spray nozzle directedupwardly into each cell and a waste drainage port leading therefrom,

a liquid supply tank carried by the other side of said platen movabletherewith,

a pump carried by said platen having its inlet connected with said tankand its discharge connected with said spray nozzles for circulating theliquid through said cells and tank during an ice forming freezing cycle,wherein ice is formed within said cells and upon said platen head duringthe freezing cycle and freed therefrom during a defrosting cycle,

a pressure exerting member mounted on said machine engageable with saidplaten in a direction to depress it for forced separation from saidevaporatorand ice and power means operable to actuate said memberfollowing the said freezing cycle,

a cam having a first part having a first center of curvature and asecond part having a second center of curvature,

said cam being mounted on a shaft disposed at a position spaced fromsaid first center of curvature and from said second center of curvature,

said cam adapted to exert a force of small magnitude to take up slack, aforce of large magnitude to break said platen loose from said ice, thena force of small magnitude to force said platen open, during threesubstantially equal angular excursions of said cam respectively.

1. In a machine for manufacturing ice comprising an evaporator unitincluding a plurality of open bottom ice forming cells, means forintroducing a liquid to be frozen into said cells to be subjected toalternate freezing and defrosting cycles, a platen movable to evaporatorclosing position during an ice freezing cycle and to an open icedischarge position during a defrosting cycle, wherein ice is formed insaid cells and upon said platen during the freezing cycle and freed fromsaid cells during the defrosting cycle, a cam shaft mounted on saidmachine above said platen, a cam on said shaft engageable with saidplaten, and power means operable following the said freezing cycle toactuate said cam shaft and cam to depress said platen for forcedseparation from said evaporator and ice upon said cam being rotated toone position and permit said platen to close said evaporator when saidcam is moved to another position, said cam having a first part having afirst center of curvature and a second part having a second center ofcurvature, said cam being mounted on said shaft at a position spacedfrom said first center of curvature and from said second center ofcurvature whereby a double eccentric cam is formed, said cam beingadapted to move said platen first through a large excursion with a smallforce to take up slack in the platen, then through a small excursionwith a larger force to move said platen open.
 2. In a machine formanufacturing ice comprising an evaporator unit including a plurality ofopen bottom ice forming cells, means for introducing a liquid to befrozen into said cells adapted to be subjected to alternate freezing anddefrosting cycles, a platen having one end pivotally mounted adjacentsaid evaporator unit and the other end free to swing to evaporatorclosing position during an ice freezing cycle and to an open icedischarging position during a defrosting cycle, wherein ice is formed insaid cells and upon said platen during said frEezing cycle and freedfrom said cells during said defrosting cycle, a cam shaft mounted onsaid machine extending over said platen adjacent the free end thereof, acam on said shaft engageable with the free end of said platen, and powermeans operable to rotate said shaft and cam one revolution following thesaid freezing cycle for moving cam from a position to permit said platento close said evaporator to a position to break it away from the iceformed therein and permit free swinging thereof to its open icedischarging position, said cam having a first part having a first centerof curvature and a second part having a second center of curvature, saidcam being mounted on said shaft disposed at a position spaced from saidfirst center of curvature and from said second center of curvature, andadapted to exert a force of small magnitude to take up slack, a force oflarge magnitude to break said platen loose from said ice, then a forceof small magnitude to force said platen open, during three substantiallyequal angular excursions of said cam respectively.
 3. In a machine formanufacturing ice comprising an evaporator unit including a plurality ofopen bottom ice forming cells, a platen movable into and away fromsealing engagement with said evaporator, a liquid supply tank carried bysaid platen, a liquid supply head in said platen having a spray nozzledirected upwardly and centrally of each cell and a waste drainage portleading therefrom to said supply tank, and a pump carried by said platenadjacent said tank having its inlet connected with said tank and itsdischarge connected with said spray nozzles for circulating the liquidto be frozen through said cells and tank, the platen, supply tank, pumpand liquid passage therebetween being a rigid unitary structure andhinged at one end of the platen to permit said structure to swingdownwardly and away from the under side of said evaporator, and powermeans operable between another edge of the platen and evaporator forforcibly breaking the ice seal, a cam having a first part having a firstcenter of curvature and a second part having a second center ofcurvature, said cam being mounted on a shaft disposed at a positionspaced from said first center of curvature and from said second centerof curvature, said cam adapted to exert a force of small magnitude totake up slack, a force of large magnitude to break said platen loosefrom said ice, then a force of small magnitude to force said platenopen, during three substantially equal angular excursions of said camrespectively.
 4. In a machine for manufacturing ice comprising anevaporator unit including a plurality of open bottom ice forming cells,a platen movable into and away from sealing engagement with saidevaporator, a liquid supply head in said platen having a spray nozzledirected upwardly into each cell and a waste drainage port leadingtherefrom, a liquid supply tank secured to and carried by said platen, apump mounted on said platen having its inlet connected with said tankand its discharge connected with said spray nozzles for circulating theliquid to be frozen through said cells and tank, a source of liquidconnected with said tank having a control valve, and a float in saidtank operably connected with said valve for limiting the liquid leveltherein, said platen, liquid supply head, supply tank, pump andinterconnecting passages being assembled as a rigid unitary structureand relatively movable as a unit with respect to said evaporator, a camhaving a first part having a first center of curvature and a second parthaving a second center of curvature, said cam being mounted on a shaftdisposed at a position spaced from said first center of curvature andfrom said second center of curvature, said cam adapted to exert a forceof small magnitude to take up slack, a force of large magnitude to breaksaid platen loose from said ice, then a Force of small magnitude toforce said platen open, during three substantially equal angularexcursions of said cam respectively.
 5. In a machine for manufacturingice comprising an evaporator unit including a plurality of open bottomice forming cells, a platen, said platen being hinged at one side toswing into and away from sealing engagement with said evaporator, aliquid supply head in said platen having a spray nozzle directedupwardly into each cell and a waste drainage port leading therefrom, aliquid supply tank carried by the other side of said platen movabletherewith, a pump carried by said platen having its inlet connected withsaid tank and its discharge connected with said spray nozzles forcirculating the liquid through said cells and tank during an ice formingfreezing cycle, wherein ice is formed within said cells and upon saidplaten head during the freezing cycle and freed therefrom during adefrosting cycle, a pressure exerting member mounted on said machineengageable with said platen in a direction to depress it for forcedseparation from said evaporator and ice, and power means operable toactuate said member following the said freezing cycle, a cam having afirst part having a first center of curvature and a second part having asecond center of curvature, said cam being mounted on a shaft disposedat a position spaced from said first center of curvature and from saidsecond center of curvature, said cam adapted to exert a force of smallmagnitude to take up slack, a force of large magnitude to break saidplaten loose from said ice, then a force of small magnitude to forcesaid platen open, during three substantially equal angular excursions ofsaid cam respectively.